An Etymological Dictionary of Astronomy and Astrophysics
English-French-Persian

فرهنگ ریشه شناختی اخترشناسی-اخترفیزیک

M. Heydari-Malayeri    -    Paris Observatory

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Number of Results: 13048 Search : far
fragmentation process
  فراروند ِ لتپارش   
farâravand-e latpâreš

Fr.: processus de fragmentation   

The succession of physical events that results in the breaking of a → molecular cloud into several → fragments.

fragmentation; → process.

frame
  ۱) چارچوب؛ ۲)، ۳) تصویرک   
1) cârcub (#); 2), 3) tasvirak

Fr.: 1) cadre; 2), 3) image   

1) A border or case for enclosing a picture, mirror, etc.; a structure for admitting or enclosing something.
2) One of the successive pictures on a roll of movie film or videotape.
3) In computers, the information or image on a screen or monitor at any one time.

Frame, from M.E. verb framen "to prepare (timber)," from O.E. framian "to avail, profit."; cf. O.H.G. (gi)framon "to do."

1) Cârcub "frame," from câr, contraction of cahâr "four" (→ four) + cub "stick, satff, beam," Mid.Pers. côp "wood, stick." 2) Tasvirak from Ar. tasvir "image" + -ak suffix of relation and similarity (as in poštak, dastak, nâxonak), → fibril.

frame dragging
  کرّه‌ی ِ چارچوب، چارچوب-کرّه   
kerre-ye cârcub, cârcub-kerré

Fr.: entraînement des repères, effet Lense-Thirring   

The alteration in the → free fall motion of a test → mass in the presence of a massive → rotating object, as compared to the identical case of a non-rotating object. This dragging of → inertial frames is predicted by → general relativity. Also called → Lense-Thirring effect.

frame; → drag.

frame frequency
  بسامد ِ تصویر   
basâmad-e tasvir

Fr.: fréquence image   

The number of times per second that the frame is scanned in television. Also known as picture frequency.

frame; → frequency.

frame of reference
  چارچوب ِ بازبرد   
câcub-e bâzbord

Fr.: système de référence   

A set of axes to which positions and motions in a system can be referred.

frame; → reference.

framing
  چارچوبش   
cârcubeš

Fr.: cadrage   

The process of adjusting a television picture to a desired position in the direction of progression.

From → frame + → -ing.

Cârcubeš, verbal noun of cârcubidan, from cârcubframe.

francium
  فرانسیوم   
frânsiom (#)

Fr.: francium   

An extremely rare radioactive chemical element; symbol Fr. Atomic number 87; atomic weight of most stable isotope 223; melting point about 27°C; boiling point about 677°C. Its most stable isotope (half-life about 22 minutes) occurs naturally, to a very limited extent, in uranium minerals. More than 30 other isotopes of francium are known; some are prepared by bombarding thorium with protons, deuterons, or alpha particles.

From France, where the French physicist Marguerite Perey (1919-1975) discovered it in 1939 in the alpha particle decay of actinium.

Fraunhofer line
  خط ِ فراؤنهوفر   
xatt-e Fraunhofer

Fr.: raie de Fraunhofer   

One of many absorption lines and bands in the spectrum of the Sun. The most prominent features are labeled with capital letters A to K, starting at the red end. The A and B bands are now known to be caused by absorption in Earth's atmosphere, while the rest are due to absorption in the Sun's → photosphere. C and F are now better known as H-alpha and H-beta (→ Balmer series); the → D lines are of sodium, the → H and K lines of calcium, and the G band of neutral iron and the interstellar → CH (methylidine) molecule.

Named after Joseph von Fraunhofer (1787-1826), German optician and physicist, who discovered these lines in 1814; → line.

Fraunhofer's refractor
  شکست‌گر ِ فراؤنهوفر   
šekastgar-e Fraunhofer

Fr.: réfracteur de Fraunhofer   

The first modern refracting telescope which had an outstanding quality. It was built in 1824 by Fraunhofer for the Russian Imperial Observatory in Dorpat, now Tartu in Estonia. It had a 23-cm → achromatic lens and a German-type → equatorial mounting driven by a clockwork. Wilhelm Struve (1793-1864) used the refractor to observe many → visual binaries, and attempted to measure the distances of stars through their visual → parallaxes. He also obtaibned accurate values for the diameters of the → Galilean satellites of → Jupiter.

Named after Joseph von Fraunhofer (1787-1826), German optician and physicist; → refractor.

free
  آزاد   
âzâd (#)

Fr.: libre   

Not physically bound by something.
free atmosphere, → free body, → free charge, → free electron, → free expansion phase, → free fall, → free flow, → free occurrence, → free oscillation, → free radical, → free system, → free-bound emission, → free-fall time, → free-floating object, → free-free emission, → freedom, → bound-free transition, → force-free magnetic field, → Gibbs free energy, → Helmholtz free energy, → mean free path, → universality of free fall.

From M.E. fre, O.E. freo "free, exempt from," also "noble, joyful;" cf. Ger. frei, Du. vrij; ultimately from PIE *prijos "dear, beloved;" cf. Av. frāy- "to satisfy, propitiate," friθa- "beloved; dear," friθô.tara- "more beloved," Mod.Pers. fari "happy, fortunate, blessed; pleasing, good," Skt. priyá- "beloved, wished for;" Gk. praos "mild, gentle."

Âzâd "free," from Mid.Pers. âzât "free, noble;" Av. āzāta- "high-born, noble," from zan- "to bear, give birth to a child, be born," infinitive zazāite, zāta- "born," āsna- "innate, natural;" cf. Skt. janati "begets, bears;" Gk. gignesthai "to become, happen," genes "born;" L. gignere "to beget;" PIE base *gen- "to give birth, beget."

free atmosphere
  جو ِ آزاد، هواسپهر ِ ~   
javv-e âzâd, havâsepehr-e ~

Fr.: atmosphère libre   

That part of the atmosphere where the effects of the ground on the → turbulence conditions are negligible.

free, → atmosphere.

free body
  جسم ِ آزاد   
jesm-e âzâd (#)

Fr.: corps libre   

A → rigid body not constrained with other bodies and which from any given position can be displaced in any direction in space. Opposite of → constrained body.

free; → body.

free charge
  بارِ آزاد   
bâr-e âzâd

Fr.: charge libre   

An electric charge which is not held by another charge, in contrast to a → bound charge.

free; → charge.

free electron
  الکترون ِ آزاد   
elektron-e âzâd (#)

Fr.: électron libre   

An electron that is not attached to an → atom, → molecule, or → ion and is free to move under the influence of a present electric or magnetic field.

free; → electron.

free expansion phase
  فاز ِ سپانش ِ آزاد   
fâz-e sopâneš-e âzâd

Fr.: phase d'expansion libre   

The first phase of → supernova remnant (SNR) evolution in which the surrounding → interstellar medium (ISM) has no influence on the expansion of the → shock wave, and the pressure of the interstellar gas is negligible. The shock wave created by the → supernova explosion moves outward into the interstellar gas at highly → supersonic speed. Assuming that most of the → supernova energy  ESN is transformed into → kinetic energy of the ejected gas, the ejection velocity ve can be estimated from ESN by using ESN = (1/2) Meve2, which leads to ve = (2ESN / Me)(1/2), where Me is the ejected mass. The schematic structure of the SNR at this phase can be described as follows: behind the strong → shock front which moves outward into the ISM, compressed interstellar gas accumulates forming a → shell of interstellar gas. This shell of swept-up material in front of shock does not represent a significant increase in the mass of the system. After some time the accumulated mass equals the ejected mass of stellar material, and it will start to affect the expansion of the SNR. By definition, this is the end of the free expansion phase, and the corresponding radius of the SNR, called → sweep-up radius, RSW, is defined by Me = (4π/3) RSW3ρ0, that is RSW = (3Me / 4πρ0)(1/3), where ρ0 is the initial density of the ISM. This radius is reached at the sweep-up time tSW = RSW/ve. The free expansion phase lasts some 100-200 years until the mass of the material swept up by the shock wave exceeds the mass of the ejected material. Then the following → snowplow phase starts.

free; → expansion; → phase.

free fall
  افت ِ آزاد   
oft-e âzâd (#)

Fr.: chute libre   

The motion of a body under the influence of → gravity alone. See also → free-fall time.

free; → fall.

free flow
  تچان ِ آزاد   
tacân-e âzâd

Fr.: écoulement libre   

A fluid flow which develops when density differences within the fluid are the only driving forces. See also → forced flow.

free; → flow.

free occurrence
  رخداد ِ آزاد   
roxdâd-e âzâd

Fr.: occurrence libre   

An → occurrence of a → variable in a → wff, → iff it is not a → bound occurrence.

bound; → occurrence.

free oscillation
  نَوِش ِ آزاد   
naveš-e âzâd

Fr.: oscillation libre   

Oscillation of any system in stable equilibrium under the influence of internal forces only, or of a constant force originating outside the system, or of both.

free; → oscillation.

free radical
  رادیکال ِ آزاد   
râdikâl-e âzâd

Fr.: radical libre   

A chemical radical that can exist independently from atoms or group of atoms.

free; → radical.

<< < -es -iv -ti 21 a p abe abs abs aca acc acc acr act ada adh Adr aer AGB air Alf Alg all alp alt AM amo ana And ang ani ano Ant Ant apa apo app app Ara Arc ari Arr ash ass ast ast asy atm ato att aut ave axi Bab bal Bal bar bar bea Bek Bes bia Big bin bin bip biv bla bli blu Boh Bol Bos bou bra bri bro buo cal cal can cap car Car cat cat CCD Cen cen CH cha cha che Che chr cir cir cit cla clo clo clu Coa coe coh col col col com com com com com com com com Com con con con con con con con con con con con con Cop Cor cor cor cos cos cou cou Cow cre cri cro cry cur cya Cyg dan dar dat de- deb dec dec ded def deg del dem den dep des det dev dia dif dif dih dio Dir dis dis dis dis dis dis DO don dou dow dro dur dwa dyn Dys ear ebb ecl edg egg Ein Ela ele ele ele ele ell eme emp enc eng ent epi equ equ equ esc eth Eur Eve exa exc exe exi exp exp ext ext ext fac fal far fed Fer fer fie fin fir fis fla flo flu fol for for fou fra fre Fre fro fut G-t gal gal gam gas Gau Gem gen geo geo geo gia Gli Gol gra gra gra gra gre gri gui H I Hag hal har hat He- hea hel Hel her Hes hie hig his hom hor hot Hub Hug hur hyd hyd hyg hyp ice ide ima Ima imp imp inc inc ind ine inf inf inf ing inn ins ins int int int int int int int int inv Io ion iro isl iso iso Jac jet jud jur Kel Kep kil Klo Kui Lag lam Lap Lar lat law lea len lep Lib lig lim lin lin Lio lit loc LOF lon Lor low lum lun Lup Lyo mac mag mag mag mag mag mai man Mar mas mas mat Max mea mec Meg Mer Mer met met Met mic Mid Mil min Mir mit mod mod mol mon Mor mou mul mul mys nan Nat nau nec neo neu nev New NGC no nom non non nor not nuc nuc num nut obj obs obs occ ocu oft ome Oor ope opp opt opt orb ord ori ort osc out ove oxi pai pan par par par par pas pea pen per per per per Per per pha phi pho pho pho phy pio Pla pla pla pla Pla plu Poi pol pol pol poo pos pos pot pra pre pre pre pre pri pri pro pro pro pro pro Pro pro pse pul pur qua qua qua qua que rac rad rad rad rad rad rad ran rar ray rea rea rec rec red red ref ref reg rel rel rel ren res res res res ret rev Ric rig rin roc roo rot rot Rus Sac sal sat sca sca Sch sci Scu sec sec Sed sel Sel sen ser Sex Sha she sho sid sig sil sim sin siz sla Sma sno sof sol sol sol sol sou sou spa spa spe spe spe sph spi spi spr squ sta sta sta sta ste ste ste Sto Str str str sub sub suc sun sup sup sup sup sur swa syn syn tab tar tek tem ter tes the the the the Tho thr tid tim Tis Too Tor tra tra Tra tra tra tri tri tru Tul tur two Typ ult un- und uni uni unk upp Urc utt val var vec vel ver vib vio vir vis voi vor wan wat wav wax wea Wei whi Wil win WN9 wor X-r yel you zer zod > >>